Embryology: Embryology (from Greek words embryon which means unborn embryo and logia which means study) is a branch of science which deals with the development of an embryo starting from the fertilization of the ovum till the fetous stage.

Histology: Histology is concerned with the study of the microscopic anatomy of cells and tissues of plants and animals. It is based on the examination of very thin slices (also known as sections) of tissue under a light microscope or electron microscope. Histological stains help to differentiate and visualize or differentially various parts of the section. Histology is a fundamental tool of study different branches of biology and medicine.